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1/*2 * Linear conversion Plug-In3 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>4 *5 *6 * This library is free software; you can redistribute it and/or modify7 * it under the terms of the GNU Library General Public License as8 * published by the Free Software Foundation; either version 2 of9 * the License, or (at your option) any later version.10 *11 * This program is distributed in the hope that it will be useful,12 * but WITHOUT ANY WARRANTY; without even the implied warranty of13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the14 * GNU Library General Public License for more details.15 *16 * You should have received a copy of the GNU Library General Public17 * License along with this library; if not, write to the Free Software18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA19 *20 */21 22#include <linux/time.h>23#include <sound/core.h>24#include <sound/pcm.h>25#include "pcm_plugin.h"26 27static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,28 const struct snd_pcm_plugin_channel *src_channels,29 struct snd_pcm_plugin_channel *dst_channels,30 snd_pcm_uframes_t frames)31{32 unsigned int channel;33 unsigned int nchannels;34 35 if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))36 return -ENXIO;37 if (frames == 0)38 return 0;39 nchannels = plugin->src_format.channels;40 for (channel = 0; channel < nchannels; channel++) {41 if (snd_BUG_ON(src_channels->area.first % 8 ||42 src_channels->area.step % 8))43 return -ENXIO;44 if (snd_BUG_ON(dst_channels->area.first % 8 ||45 dst_channels->area.step % 8))46 return -ENXIO;47 if (!src_channels->enabled) {48 if (dst_channels->wanted)49 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);50 dst_channels->enabled = 0;51 continue;52 }53 dst_channels->enabled = 1;54 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);55 src_channels++;56 dst_channels++;57 }58 return frames;59}60 61int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug,62 struct snd_pcm_plugin_format *src_format,63 struct snd_pcm_plugin_format *dst_format,64 struct snd_pcm_plugin **r_plugin)65{66 int err;67 struct snd_pcm_plugin *plugin;68 int width;69 70 if (snd_BUG_ON(!r_plugin))71 return -ENXIO;72 *r_plugin = NULL;73 74 if (snd_BUG_ON(src_format->format != dst_format->format))75 return -ENXIO;76 if (snd_BUG_ON(src_format->rate != dst_format->rate))77 return -ENXIO;78 if (snd_BUG_ON(src_format->channels != dst_format->channels))79 return -ENXIO;80 81 width = snd_pcm_format_physical_width(src_format->format);82 if (snd_BUG_ON(width <= 0))83 return -ENXIO;84 85 err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,86 0, &plugin);87 if (err < 0)88 return err;89 plugin->transfer = copy_transfer;90 *r_plugin = plugin;91 return 0;92}93